Open-End Winding Induction Motor Drive Based on Indirect Matrix Converter

Open-end winding induction machines fed from two standard two-level voltage source inverters (VSI) provide an attractive arrangement for AC drives. An alternative approach is to use a dual output indirect matrix converter (IMC). It is well known that IMC provides fully bidirectional power flow operation, with small input size filter requirements. Whilst a standard IMC consists of an AC–DC matrix converter input stage followed by a single VSI output stage, it is possible to replicate the VSI to produce multiple outputs. In this chapter, an open-end winding induction machine fed by an IMC with two output stages is presented. Different modulation strategies for the power converter are analyzed and discussed

Dual‐Inverter Circuit Topologies for Supplying Open‐Ended Loads

Power electronic converters are nowadays the most suitable solution to provide a variable voltage/current in industry. The most commonly used power converter is the three-phase two-level voltage source inverter which transforms a direct-current input voltage into alternating-current output voltage with adjustable magnitude and frequency. Power inverters are used to supply three-phase loads which are typically connected in wye or delta configurations. However, in previous years, a type of connection consisting on leaving both terminal ends of the load opened has been studied as an alternative to standard wye or delta connection. To supply loads with this type of connection, two power inverters (one at each terminal end of the load) are required in a circuit topology called dual-inverter. In this chapter, a general study of the dual-inverter topology is presented. The advantages and issues of such converter are studied and different modulation strategies are shown and discussed. Moreover, multilevel dual-inverter converters are presented as an extension to the basic two-level idea. For evaluation purposes, simulations results are presented

Power control of a grid-connected PV system during asymmetrical voltage faults

[EN] Under voltage faults, grid-tied photovoltaic inverters should remain connected to the grid according to fault ride-through requirements. Moreover, it is a desirable characteristic to keep the power injected to grid constant during the fault. This paper explores a control strategy to regulate the active and reactive powers delivered by a single-stage photovoltaic generation system to the grid during asymmetrical voltage faults. The reference for the active power is obtained from a maximum power point tracking algorithm, whereas the reference for the reactive power can be set freely if the zero-sequence voltage is null; otherwise, it will depend on the magnitude of the zero-sequence voltage and the active power reference. The power control loop generates the reference currents to be imposed by the grid-tied power inverter. These currents are regulated by a predictive controller. The proposed approach is simpler than other methods proposed in the literature. The performance of the control strategy presented is verified with an experimental laboratory setup where voltage sags and swells are considered.This work was funded by Conicyt Chile Under Project FONDECYT 11180092. The financial support given by CONICYT/FONDAP/15110019 is also acknowledged.Hunter, G.; Riedemann, J.; Andrade, I.; Blasco-Gimenez, R.; Peña, R. (2019). Power control of a grid-connected PV system during asymmetrical voltage faults. Electrical Engineering. 101(1):239-250. https://doi.org/10.1007/s00202-019-00769-x2392501011Greentech Media Research “By 2023, the world will have 1 trillion Watts of installed solar PV capacity”. https://www.greentechmedia.com/articles/read/by-2023-the-world-will-have-one-trillion-watts-of-installed-solar-pv-capaciSubudhi B, Pradhan R (2013) A comparative study on maximum power point tracking techniques for photovoltaic power systems. 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In: 2017 IEEE applied power electronics conference and exposition (APEC), Tampa, FL, pp 1357–1362L Hi, Xu Y, Adhikari S, Rizy DT, Li F, Irminger P (2012) Real and reactive power control of a three-phase single-stage PV system and PV voltage stability. 2012 IEEE power and energy society general meeting, San Diego, CA, pp 1–8Shao R, Wei R, Chang L (2014) A multi-stage MPPT algorithm for PV systems based on golden section search method. 2014 IEEE applied power electronics conference and exposition—APEC 2014, Fort Worth, TX, pp 676–683Zapata JW, Kouro S, Aguirre M, Meynard T (2015) Model predictive control of interleaved dc-dc stage for photovoltaic microconverters. Industrial Electronics Society, IECON 2015 - 41st annual conference of the IEEE, Yokohama, pp 004311–004316Dousoky GM, Ahmed EM, Shoyama M (2013) “MPPT schemes for single-stage three-phase grid-connected photovoltaic voltage-source inverters. In: 2013 IEEE international conference industrial technology (ICIT), pp 600–605Electricity System Operator (ESO). www.nationalgrideso.comAl-Shetwi A, Sujod M, Blaabjerg F, Yang Y (2019) Fault ride-through control of grid-connected photovoltaic power plants: a review. Sol Energy 180:340–350Almeida P, Monteiro K, Barbosa P, Duarte J, Ribeiro P (2016) Improvement of PV grid-tied inverters operation under asymmetrical fault conditions. Sol Energy 133:363–371Ding G, Gao F, Tian H, Ma C, Chen M, He G, Liang Y (2016) Adaptive DC-link voltage control of two-stage photovoltaic inverter during low voltage ride-through operation. IEEE Trans Power Electron 31:4182–4194Miret J, Castilla M, Camacho A, Vicuña LGd, Matas J (2012) Control scheme for photovoltaic three-phase inverters to minimize peak currents during unbalanced grid-voltage sags. In: IEEE transactions on power electronics, vol 27, pp 4262–4271Naderi S, Negnevitsky M, Jalilian A, Hagh M (2016) Efficient fault ride-through scheme for three phase voltage source inverter-interfaced distributed generation using DC link adjustable resistive type fault current limiter. Renew Energy 92:484–498Merabet A, Labib L, Ghias AMYM (2018) Robust model predictive control for photovoltaic inverter system with grid fault ride-through capability. IEEE Trans Smart Grid 9:5699–5709Ting-Chia Ou (2012) A novel unsymmetrical faults analysis for microgrid distribution systems. Electr Power Energy Syst 43:1017–1024Lin W, Ou T (2011) Unbalanced distribution network fault analysis with hybrid compensation. IET Gener Transm Distrib 5:92–100Ting-Chia Ou (2013) Ground fault current analysis with a direct building algorithm for microgrid distribution. Electr Power Energy Syst 53:867–875Ou T-C, Lu K-H, Huang C-J (2017) Improvement of transient stability in a hybrid power multi-system using a designed NIDC (novel intelligent damping controller). Energies 10:488Sadeghkhani I, Hamedani M, Guerrero J, Mehrizi-Sani Ali (2017) A current limiting strategy to improve fault ride-through of inverter interfaced autonomous microgrids. IEEE Trans Smart Grid 8:2138–2148Junyent-Ferre A, Gomis-Bellmunt O, Green T, Soto-Sanchez D (2011) Current control reference calculation issues for the operation of renewable source grid interface VSCs under unbalanced voltage sags. IEEE Trans Power Electron 26(12):3744–3753Castilla M, Miret J, Sosa JL, Matas J, de Vicuña LG (2010) Grid-fault control scheme for three-phase photovoltaic inverters with adjustable power quality characteristics. IEEE Trans Power Electron 25(12):2930–2940Camacho A, Castilla M, Miret J, Vasquez JC, Alarcón-Gallo E (2013) Flexible voltage support control for three-phase distributed generation inverters under grid fault. IEEE Trans Ind Electron 60(4):1429–1441Sosa JL, Castilla M, Miret J, Matas J, Al-Turki YA (2016) Control strategy to maximize the power capability of PV three-phase inverters during voltage sags. IEEE Trans Power Electron 31(4):3314–3323Lin F-J et al (2015) Reactive power control of three-phase grid-connected PV system during grid faults using Takagi–Sugeno–Kang probabilistic fuzzy neural network control. IEEE Trans Ind Electron 62(9):5516–5528Hunter G, Andrade I, Riedemann J, Blasco-Gimenez R, Peña R (2016) Active and reactive power control during unbalanced grid voltage in PV systems. In: IECON 2016 - 42nd Annual Conference of the IEEE Industrial Electronics Society, Florence, pp 3012–3017Rodrıguez J, Pontt J, Silva CA, Correa P, Lezana P, Cortes P, Ammann U (2007) Predictive current control of a voltage source inverter. IEEE TransInd Electron 54(1):495–503Shadmand MB, Balog RS, Abu-Rub H (2014) Model predictive control of PV sources in a smart DC distribution system: maximum power point tracking and droop control. IEEE Trans Energy Convers 29(4):913–921Lei M et al (2018) An MPC-based ESS control method for PV power smoothing applications. IEEE Trans Power Electron 33(3):2136–2144Hussain I, Singh B (2014) Grid integration of large capacity solar PV plant using multipulse VSC with robust PLL based control. In: Power India International Conference (PIICON), 2014 6th IEEE, Delhi, pp 1–6Bayrak G, Kabalci E, Cebecı M (2014) Real time power flow monitoring in a PLL inverter based PV distributed generation system. 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An Active/Reactive Power Control Strategy for Renewable Generation Systems

[EN] The development of distributed generation, mainly based on renewable energies, requires the design of control strategies to allow the regulation of electrical variables, such as power, voltage (V), and frequency (f), and the coordination of multiple generation units in microgrids or islanded systems. This paper presents a strategy to control the active and reactive power flow in the Point of Common Connection (PCC) of a renewable generation system operating in islanded mode. Voltage Source Converters (VSCs) are connected between individual generation units and the PCC to control the voltage and frequency. The voltage and frequency reference values are obtained from the P-V and Q-f droop characteristics curves, where P and Q are the active and reactive power supplied to the load, respectively. Proportional-Integral (PI) controllers process the voltage and frequency errors and set the reference currents (in the dq frame) to be imposed by each VSC. Simulation results considering high-power solar and wind generation systems are presented to validate the proposed control strategy.This research was funded by ANID/FONDAP/15110019, by ANID/FONDECYT/1201616, and by ANID/PIA/ACT192013. This work was also supported by the Spanish Ministry of Economy and EU FEDER Funds under grant DPI2017-84503-R. Project partially funded by the EU through the Comunitat Valenciana 2014-2020 European Regional Development Fund (FEDER) Operating Program (grant IDIFEDER/2018/036).Andrade, I.; Pena, R.; Blasco-Gimenez, R.; Riedemann, J.; Jara, W.; Pesce, C. (2021). An Active/Reactive Power Control Strategy for Renewable Generation Systems. Electronics. 10(9):1-19. https://doi.org/10.3390/electronics1009106111910

Power flow control using a DC-DC MMC for HVdc grid connected wind power plants

This paper proposes the use of a transformer-less DC-DC Modular Multilevel Converter (MMC) topology, based on cascaded H-bridge converters, for power flow control in High Voltage Direct Current (HVDC) grids used to connect off-shore wind power plants to on-shore grids. An energy based approach is used to regulate the DC voltage of H-bridge modules. Results for the operation of the DC-DC MMC supplying energy to a DC network and controlling the power flow in a HVDC system are presented.The support of Fondecyt grant 1151325, CONICYT/FONDAP/15110019, the Spanish Ministry of Economy Grant DPI2014-53245-R, University La Frontera grant DIUFRO09-0037 and Universitat Jaume I grants P1ā1B2013-51 and E-2014-24 is kindly acknowledged

Modulation strategies for an open-end winding induction machine fed by a two-output indirect matrix converter

This paper presents a two-output indirect matrix converter feeding an open-ended winding induction machine. The modulation strategy for the converter input stage, which provides the DC voltage for the output stages, exploits the capability of the input rectifier to produce different DC voltage levels. Moreover, this paper includes a space vector modulation strategy for the converter output stages intended to eliminate the zero sequence load voltage. Furthermore, in order to decrease commutation losses, output stage commutation will take place at reduced voltage when load voltage requirements are low. Modulation strategies and overall system operation are verified via simulation in a PSim/Matlab platform with the machine operating under an open loop V/f control strategy. Experimental results are also presented to validate the control strategies

Vector control of an open-ended winding induction machine based on a two-output indirect matrix converter

The open-ended winding induction machine fed from a standard two-level Voltage Source Inverter (VSI) arrangement is an attractive solution for AC drives. An alternative power converter approach is to use an Indirect Matrix Converter (IMC) consisting of a matrix converter AC-DC input stage and two VSI output stages. This latter topology provides fully bidirectional power flow operation and requires only a small input filter. In this paper, a vector control strategy for an open-ended winding cage induction machine fed by a two-output IMC is presented. The modulation scheme for the input power converter stage aims to modify the virtual DC link voltage depending on the load voltage requirement. Additionally, the modulation strategy for the dual-inverter output aims to eliminate the zero sequence voltage applied to the load. A vector control scheme is used and the full system is modelled using a PSIM and MATLAB/Simulink platform. Experimental results from a 7.5 kW prototype are presented, demonstrating the feasibility of the topology and control strategy

DC Current Harmonics Reduction in Multi-Inverter Topology

[EN] This letter presents a Space Vector Pulse Width Modulation (SVPWM) strategy for reducing the DC-link current harmonics in a multi- Voltage Source Inverter (VSI) topology with common DC-link bus. The DC current harmonic reduction is achieved by phase-shifting the PWM pattern of individual VSIs, with the inverters sharing the system total power. Simulation and experimental results are shown to validate the proposal.This work was supported by ANID/FONDAP/15110019 and in part by ANID/FONDECYT/1201616.Reyes, E.; Sarasiri, N.; Pena, R.; Riedemann, J.; Andrade, I.; Blasco-Giménez, R.; Jara, W. (2022). DC Current Harmonics Reduction in Multi-Inverter Topology. IEEE Transactions on Power Delivery. 37(5):4489-4492. https://doi.org/10.1109/TPWRD.2022.31841874489449237

Narrativas sobre diversidad cultural y migración en escuelas de Chile

Este artículo de investigación explora,desde la interculturalidad crítica,los principales enunciados de las tramas narrativas de diferentes actores escolares chilenos (docentes, asistentes y directores) con respecto a los desafíos que la multiculturalidad representa para su práctica pedagógica, a partir de un estudio cualitativo desarrollado en cinco escuelas de tres comunas de la Región Metropolitana (Independencia, Recoleta y Quilicura). Se identifican enunciados enmarcados en dos tipos generales de discurso: uno asimilacionista y universalizador, y otro de la tolerancia y la hibridez.Se concluye que ambos suponen una mirada funcional de la interculturalidad que es preciso problematizar,considerando las prácticas pedagógicas en que se materializan.This article explores from the critical interculturality the main tenets of the narrative accounts by different school actors in Chile (teachers,assistants,directors) regarding the challenges that the multiculturality poses to the teaching practice.This work is based on a qualitative study developed in five schools in three different neighborhoods of the Metropolitan Area (Independencia,Recoleta and Quilicura).The tenets identified are framed under two general discursive types:a first one,driven towards assimilation and universalization;a second one,related to the tolerance and hybridity. Both types provides a functional view of the interculturality that must be questioned by taking into consideration the pedagogical practices where they become materialized

A Modified Step-Up DC-DC Flyback Converter with Active Snubber for Improved Efficiency

The research on DC-DC power converters has been a matter of interest for years since this type of converter can be used in a wide range of applications. The main research is focused on increasing the converter voltage gain while obtaining a good efficiency and reliability. Among the different DC-DC converters, the flyback topology is well-known and widely used. In this paper, a novel high efficiency modified step-up DC-DC flyback converter is presented. The converter is based on a N-stages flyback converter with parallel connected inputs and series-connected outputs. The use of a single main diode and output capacitor reduces the number of passive elements and allows for a more economical implementation compared with interleaved flyback topologies. High efficiency is obtained by including an active snubber circuit, which returns the energy stored in the leakage inductance of the flyback transformers back to the input power supply. A 4.7 kW laboratory prototype is implemented considering four flyback stages with an input voltage of 96 V and an output voltage of 590 V, obtaining an efficiency of 95%. The converter operates in discontinuous current mode then facilitating the output voltage controller design. Experimental results are presented and discussed